Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 810
Filtrar
1.
J Med Chem ; 64(1): 71-100, 2021 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-33372516

RESUMO

The alarming rise in drug-resistant clinical cases of tuberculosis (TB) has necessitated the rapid development of newer chemotherapeutic agents with novel mechanisms of action. The mycobactin biosynthesis pathway, conserved only among the mycolata family of actinobacteria, a group of intracellularly surviving bacterial pathogens that includes Mycobacterium tuberculosis, generates a salicyl-capped peptide mycobactin under iron-stress conditions in host macrophages to support the iron demands of the pathogen. This in vivo essentiality makes this less explored mycobactin biosynthesis pathway a promising endogenous target for novel lead-compounds discovery. In this Perspective, we have provided an up-to-date account of drug discovery efforts targeting selected enzymes (MbtI, MbtA, MbtM, and PPTase) from the mbt gene cluster (mbtA-mbtN). Furthermore, a succinct discussion on non-specific mycobactin biosynthesis inhibitors and the Trojan horse approach adopted to impair iron metabolism in mycobacteria has also been included in this Perspective.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/metabolismo , Oxazóis/metabolismo , Tuberculose/tratamento farmacológico , Proteínas de Bactérias/metabolismo , Vias Biossintéticas , Descoberta de Drogas , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Ferro/metabolismo , Mycobacterium tuberculosis/efeitos dos fármacos
2.
J Mol Model ; 26(12): 341, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33200284

RESUMO

HER-2 type breast cancer is one of the most aggressive malignancies found in women. Tucatinib is recently developed and approved as a potential medicine to fight this disease. In this manuscript, we present the gross structural features of this compound and its reactivity and wave function properties using computational simulations. Density functional theory was used to optimise the ground state geometry of the molecule and molecular docking was used to predict biological activity. As the electrons interact with electromagnetic radiations, electronic excitations between different energy levels are analysed in detail using time-dependent density functional theory. Various intermolecular and intermolecular interactions are analysed and reaction sites for attacking electrophiles and nucleophiles identified. Information entropy calculations show that the compound is inherently stable. Docking with COVID-19 proteins show docking score of - 9.42, - 8.93, - 8.45 and - 8.32 kcal/mol respectively indicating high interaction between the drug and proteins. Hence, this is an ideal candidate to study repurposing of existing drugs to combat the pandemic.


Assuntos
Antineoplásicos/química , Antivirais/química , Betacoronavirus/química , Elétrons , Oxazóis/química , Inibidores de Proteases/química , Piridinas/química , Quinazolinas/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Antineoplásicos/metabolismo , Antivirais/metabolismo , Betacoronavirus/enzimologia , Sítios de Ligação , Cisteína Endopeptidases/química , Cisteína Endopeptidases/metabolismo , Reposicionamento de Medicamentos , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Oxazóis/metabolismo , Inibidores de Proteases/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Piridinas/metabolismo , Teoria Quântica , Quinazolinas/metabolismo , Termodinâmica , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismo
3.
PLoS Negl Trop Dis ; 14(4): e0008162, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32275663

RESUMO

Chagas cardiomyopathy is the most severe manifestation of human Chagas disease and represents the major cause of morbidity and mortality in Latin America. We previously demonstrated diastolic Ca2+ alterations in cardiomyocytes isolated from Chagas' patients to different degrees of cardiac dysfunction. In addition, we have found a significant elevation of diastolic [Na+]d in Chagas' cardiomyocytes (FCII>FCI) that was greater than control. Exposure of cardiomyocytes to agents that enhance inositol 1,4,5 trisphosphate (IP3) generation or concentration like endothelin (ET-1) or bradykinin (BK), or membrane-permeant myoinositol 1,4,5-trisphosphate hexakis(butyryloxy-methyl) esters (IP3BM) caused an elevation in diastolic [Ca2+] ([Ca2+]d) that was always greater in cardiomyocytes from Chagas' than non- Chagas' subjects, and the magnitude of the [Ca2+]d elevation in Chagas' cardiomyocytes was related to the degree of cardiac dysfunction. Incubation with xestospongin-C (Xest-C), a membrane-permeable selective blocker of the IP3 receptors (IP3Rs), significantly reduced [Ca2+]d in Chagas' cardiomyocytes but did not have a significant effect on non-Chagas' cells. The effects of ET-1, BK, and IP3BM on [Ca2+]d were not modified by the removal of extracellular [Ca2+]e. Furthermore, cardiomyocytes from Chagas' patients had a significant decrease in the sarcoplasmic reticulum (SR) Ca2+content compared to control (Control>FCI>FCII), a higher intracellular IP3 concentration ([IP3]i) and markedly depressed contractile properties compared to control cardiomyocytes. These results provide additional and convincing support about the implications of IP3 in the pathogenesis of Chagas cardiomyopathy in patients at different stages of chronic infection. Additionally, these findings open the door for novel therapeutic strategies oriented to improve cardiac function and quality of life of individuals suffering from chronic Chagas cardiomyopathy (CC).


Assuntos
Cálcio/metabolismo , Cardiomiopatia Chagásica/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Inositol 1,4,5-Trifosfato/metabolismo , Miócitos Cardíacos/metabolismo , Adulto , Bradicinina/metabolismo , Permeabilidade da Membrana Celular , Endotelinas/metabolismo , Feminino , Humanos , Compostos Macrocíclicos/metabolismo , Masculino , Pessoa de Meia-Idade , Oxazóis/metabolismo , Qualidade de Vida , Retículo Sarcoplasmático/metabolismo , Sódio/metabolismo
4.
PLoS Pathog ; 16(2): e1008337, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32069330

RESUMO

Iron is essential for nearly all bacterial pathogens, including Mycobacterium tuberculosis (Mtb), but is severely limited in the human host. To meet its iron needs, Mtb secretes siderophores, small molecules with high affinity for iron, and takes up iron-loaded mycobactins (MBT) and carboxymycobactins (cMBT), from the environment. Mtb is also capable of utilizing heme and hemoglobin which contain more than 70% of the iron in the human body. However, many components of these iron acquisition pathways are still unknown. In this study, a high-density transposon mutagenesis coupled with deep sequencing (TnSeq) showed that Mtb exhibits nearly opposite requirements for 165 genes in the presence of heme and hemoglobin versus MBT and cMBT as iron sources. The ESX-3 secretion system was assessed as essential for siderophore-mediated iron uptake and, surprisingly, also for heme utilization by Mtb. Predictions derived from the TnSeq analysis were validated by growth experiments with isogenic Mtb mutants. These results showed that (i) the efflux pump MmpL5 plays a dominant role in siderophore secretion, (ii) the Rv2047c protein is essential for growth of Mtb in the presence of mycobactin, and (iii) the transcriptional repressor Zur is required for heme utilization by Mtb. The novel genetic determinants of iron utilization revealed in this study will stimulate further experiments in this important area of Mtb physiology.


Assuntos
Ferro/metabolismo , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Amida Sintases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Transporte Biológico , Heme/metabolismo , Hemoglobinas/metabolismo , Humanos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Mutação , Oxazóis/metabolismo , Sideróforos/metabolismo , Virulência
5.
Nat Prod Res ; 34(5): 710-713, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30445822

RESUMO

The correlation between the allocation of trisoxazole macrolides in the capitums, appendages, and bases of the sponge Penares cf. nux and the surface-attached bacteria on the corresponding parts was examined. The kabiramide contents were highest in the capitums, followed by the appendages and bases. Conversely, direct counts of cultivable surface-attached bacteria showed that the bacteria aggregate more densely on the surfaces of the bases. This suggested the repelling effects of the kabiramides against the fouling bacteria, particularly on the capitums and appendages. Twenty-two bacterial strains were isolated and identified to 15 species; however, none has shown the potentials as a producer of any secondary metabolites in the sponge P. nux.


Assuntos
Antibacterianos/metabolismo , Macrolídeos/farmacologia , Poríferos/metabolismo , Animais , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Aderência Bacteriana/fisiologia , Macrolídeos/metabolismo , Oxazóis/metabolismo , Oxazóis/farmacologia , Poríferos/química
6.
ACS Chem Biol ; 14(12): 2683-2690, 2019 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-31674754

RESUMO

Prenylation is a common step in the biosynthesis of many natural products and plays an important role in increasing their structural diversity and enhancing biological activity. Muscoride A is a linear peptide alkaloid that contain two contiguous oxazoles and unusual prenyl groups that protect the amino- and carboxy-termini. Here we identified the 12.7 kb muscoride (mus) biosynthetic gene clusters from Nostoc spp. PCC 7906 and UHCC 0398. The mus biosynthetic gene clusters encode enzymes for the heterocyclization, oxidation, and prenylation of the MusE precursor protein. The mus biosynthetic gene clusters encode two copies of the cyanobactin prenyltransferase, MusF1 and MusF2. The predicted tetrapeptide substrate of MusF1 and MusF2 was synthesized through a novel tandem cyclization route in only eight steps. Biochemical assays demonstrated that MusF1 acts on the carboxy-terminus while MusF2 acts on the amino-terminus of the tetrapeptide substrate. We show that the MusF2 enzyme catalyzes the reverse or forward prenylation of amino-termini from Nostoc spp. PCC 7906 and UHCC 0398, respectively. This finding expands the regiospecific chemical functionality of cyanobactin prenyltransferases and the chemical diversity of the cyanobactin family of natural products to include bis-prenylated polyoxazole linear peptides.


Assuntos
Oxazóis/metabolismo , Pirrolidinas/metabolismo , Vias Biossintéticas/genética , Dimetilaliltranstransferase/genética , Dimetilaliltranstransferase/metabolismo , Família Multigênica , Peptídeos Cíclicos/metabolismo , Prenilação
7.
Biomed Res Int ; 2019: 2582401, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31641668

RESUMO

Autosomal dominant polycystic kidney disease (ADPKD) is associated with a number of cellular defects such as hyperproliferation, apoptosis, and dedifferentiation. Mutations in polycystin-1 (PC1) account for ∼85% of ADPKD. Here, we showed that wild-type (WT) or mutant PC1 composed of the last five transmembrane (TM) domains and the C-terminus (termed PC1-5TMC) inhibits cell proliferation and protein translation, as well as the downstream effectors of mTOR, consistent with previous reports. Knockdown of B56α, a subunit of the protein phosphatase 2A (PP2A) complex, or application of PP2A inhibitor okadaic acid or calyculin A, abolished the inhibitory effect of PC1 and PC1-5TMC on proliferation, indicating that PP2A/B56α mediates the regulation of cell proliferation by PC1. In addition to the phosphorylated S6 and 4EBP1, B56α was also downregulated by PC1 and PC1-5TMC. Furthermore, the downregulation of B56α, which may be mediated by mTOR but not AKT, can account for the dependence of PC1-inhibited proliferation on PP2A.


Assuntos
Proliferação de Células/efeitos dos fármacos , Proteína Fosfatase 2/metabolismo , Canais de Cátion TRPP/antagonistas & inibidores , Animais , Apoptose , Diferenciação Celular , Linhagem Celular , Regulação para Baixo , Técnicas de Silenciamento de Genes , Células HEK293 , Células HeLa , Humanos , Toxinas Marinhas , Mutação , Ácido Okadáico/metabolismo , Oxazóis/metabolismo , Fosforilação , Doenças Renais Policísticas/tratamento farmacológico , Biossíntese de Proteínas/efeitos dos fármacos , Proteína Fosfatase 2/genética , Serina-Treonina Quinases TOR/metabolismo , Canais de Cátion TRPP/genética
8.
J Med Chem ; 62(21): 9600-9617, 2019 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-31535859

RESUMO

Using structure-guided design, several cell based assays, and microdosed positron emission tomography (PET) imaging, we identified a series of highly potent, selective, and brain-penetrant oxazole-4-carboxamide-based inhibitors of glycogen synthase kinase-3 (GSK-3). An isotopologue of our first-generation lead, [3H]PF-367, demonstrates selective and specific target engagement in vitro, irrespective of the activation state. We discovered substantial ubiquitous GSK-3-specific radioligand binding in Tg2576 Alzheimer's disease (AD), suggesting application for these compounds in AD diagnosis and identified [11C]OCM-44 as our lead GSK-3 radiotracer, with optimized brain uptake by PET imaging in nonhuman primates. GSK-3ß-isozyme selectivity was assessed to reveal OCM-51, the most potent (IC50 = 0.030 nM) and selective (>10-fold GSK-3ß/GSK-3α) GSK-3ß inhibitor known to date. Inhibition of CRMP2T514 and tau phosphorylation, as well as favorable therapeutic window against WNT/ß-catenin signaling activation, was observed in cells.


Assuntos
Encéfalo/metabolismo , Descoberta de Drogas , Glicogênio Sintase Quinase 3 beta/antagonistas & inibidores , Tomografia por Emissão de Pósitrons/métodos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/diagnóstico por imagem , Domínio Catalítico , Glicogênio Sintase Quinase 3 beta/química , Células HEK293 , Humanos , Camundongos , Modelos Moleculares , Neuroimagem , Oxazóis/química , Oxazóis/metabolismo , Oxazóis/farmacologia , Inibidores de Proteínas Quinases/metabolismo , Triazóis/química , Triazóis/metabolismo , Triazóis/farmacologia
9.
Bioorg Med Chem ; 27(21): 115086, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31515057

RESUMO

Four inhibitors of human carbonic anhydrase II (hCA II) were designed based on the previously reported subnanomolar 1,3-oxazole-based sulfonamide inhibitors of the enzyme to incorporate primary and secondary amine functionality in the carboxamide side chain. The new hydrophilic compounds were found to inhibit the target isoform in sub-nanomolar to low nanomolar range with a good degree of selectivity to several other hCA isoforms. The hydrophilic character of these compounds is advantageous for intraocular residence time but not for corneal permeability which generally requires that a drug be sufficiently lipophilic. Two of the four compounds investigated, however, were found to exert comparable efficacy as 1% eye drops in PBS to that of the clinically used 2% dorzolamide (Trusopt®) eye drops. This indicated that the absorption of the compounds may occur via alternative route across conjunctiva and sclera.


Assuntos
Anidrase Carbônica II/antagonistas & inibidores , Inibidores da Anidrase Carbônica/farmacologia , Pressão Intraocular/efeitos dos fármacos , Oxazóis/farmacologia , Sulfonamidas/farmacologia , Animais , Anidrase Carbônica II/metabolismo , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/metabolismo , Humanos , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Oxazóis/síntese química , Oxazóis/metabolismo , Ligação Proteica , Coelhos , Sulfonamidas/síntese química , Sulfonamidas/metabolismo , Suínos
10.
Biomacromolecules ; 20(8): 2913-2921, 2019 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-31365234

RESUMO

A library of poly(2-oxazoline)s functionalized with controllable amounts of alendronate, hydroxyl, and carboxylic acid side groups was successfully synthesized to create novel polymers with tunable affinity for calcium cations. The affinity of alendronate-containing polymers for calcium cations was quantified using isothermal titration calorimetry. Thermodynamic measurements revealed that the Ca2+-binding affinity of these polymers increased linearly with the amount of alendronate functionalization, up to values (KCa2+ = 2.4 × 105 M-1) that were about 120-fold higher than those for previously reported polymers. The calcium-binding capacity of alendronate-functionalized poly(2-oxazoline)s was exploited to form robust hydrogel networks cross-linked using reversible physical bonds. Oscillatory rheology showed that these hydrogels recovered more than 100% of their initial storage modulus after severe network destruction. The versatile synthesis of alendronate-functionalized polymers and their strong and tunable affinity for calcium cations render these polymers promising candidates for various biomedical applications.


Assuntos
Alendronato/química , Materiais Biocompatíveis/química , Cálcio/química , Hidrogéis/química , Oxazóis/química , Polímeros/química , Alendronato/metabolismo , Materiais Biocompatíveis/metabolismo , Cálcio/metabolismo , Hidrogéis/metabolismo , Oxazóis/metabolismo , Polímeros/metabolismo , Reologia
11.
Environ Monit Assess ; 191(8): 517, 2019 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-31352622

RESUMO

The dissipation and residual levels of etoxazole and pyridaben in Goji berry under open field conditions were determined by using GC-NPD (gas chromatography with nitrogen and phosphorus detector) with modified QuEChERS method. At fortification levels of 0.01, 1, and 5 mg/kg in Goji berry, it was shown that recoveries were ranged from 80.40 to 100.9% with relative standard deviation of the method (RSD) for repeatability ranged from 2.20 to 4.25%. The limit of quantification (LOQ) of the method was 0.01 mg/kg. The dissipation rates of etoxazole and pyridaben were described by using first-order kinetics and its half-life, as they are 7.13 days, 5.77 days, and 5.99 days (etoxazole) and 1.02 day, 0.67 day, 1.02 day (pyridaben). The terminal residues of etoxazole and pyridaben were below the European maximum residue limit (MRL, 0.1 mg/kg) in Goji berry when measured 7 days after the final application, which suggested that the use of these insecticides was safe for humans. This study would help in providing the basic information for developing regulation to guard a safe use of etoxazole and pyridaben in Goji berry and prevent health problem from consumers.


Assuntos
Monitoramento Ambiental/métodos , Lycium/metabolismo , Oxazóis/análise , Resíduos de Praguicidas/análise , Piridazinas/análise , China , Meia-Vida , Humanos , Cinética , Lycium/crescimento & desenvolvimento , Oxazóis/metabolismo , Resíduos de Praguicidas/metabolismo , Piridazinas/metabolismo , Tibet
12.
Eur J Med Chem ; 176: 326-342, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31112893

RESUMO

Peroxisome Proliferator-Activated Receptors (PPARs) are ligand-activated transcription factors that govern lipid and glucose homeostasis playing a central role in cardiovascular disease, obesity, and diabetes. These receptors show a high degree of stereoselectivity towards several classes of drugs. This review covers the most relevant findings that have been made in the last decade and takes into consideration only those compounds in which stereochemistry led to unexpected results or peculiar interactions with the receptors. These cases are reviewed and discussed with the aim to show how enantiomeric recognition originates at the molecular level. The structural characterization by crystallographic methods and docking experiments of complexes formed by PPARs with their ligands turns out to be an essential tool to explain receptor stereoselectivity.


Assuntos
Derivados de Benzeno/química , Derivados de Benzeno/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Acetatos/química , Acetatos/metabolismo , Animais , Sítios de Ligação , Cristalografia por Raios X , Humanos , Indóis/química , Indóis/metabolismo , Ligantes , Simulação de Acoplamento Molecular , Oxazóis/química , Oxazóis/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/agonistas , Receptores Ativados por Proliferador de Peroxissomo/antagonistas & inibidores , Receptores Ativados por Proliferador de Peroxissomo/química , Fenilpropionatos/química , Fenilpropionatos/metabolismo , Ligação Proteica , Estereoisomerismo , Relação Estrutura-Atividade , Tirosina/análogos & derivados , Tirosina/metabolismo
13.
Methods Mol Biol ; 2001: 147-202, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31134572

RESUMO

This review describes a selection of macrocyclic natural products and structurally modified analogs containing peptidic and non-peptidic elements as structural features that potentially modulate cellular permeability. Examples range from exclusively peptidic structures like cyclosporin A or phepropeptins to compounds with mostly non-peptidic character, such as telomestatin or largazole. Furthermore, semisynthetic approaches and synthesis platforms to generate general and focused libraries of compounds at the interface of cyclic peptides and non-peptidic macrocycles are discussed.


Assuntos
Compostos Macrocíclicos/química , Peptídeos Cíclicos/química , Produtos Biológicos , Ciclização , Depsipeptídeos/química , Depsipeptídeos/metabolismo , Humanos , Lactonas/química , Lactonas/metabolismo , Compostos Macrocíclicos/síntese química , Oxazóis/química , Oxazóis/metabolismo , Biblioteca de Peptídeos , Peptídeos Cíclicos/síntese química , Peptídeos Cíclicos/metabolismo , Permeabilidade , Conformação Proteica , Compostos de Espiro/química , Compostos de Espiro/metabolismo , Estreptograminas/química , Estreptograminas/metabolismo , Tiazóis/química , Tiazóis/metabolismo
14.
Carbohydr Res ; 477: 11-19, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30933786

RESUMO

Enzymatic degradation of locust bean gum provides a Manß(1 → 4)Man disaccharide, which may be converted into the core Manß(1 → 4)GlcNAc disaccharide unit of all N-glycans via conversion to a 2-iodo-glycosyl azide, and Lafont rearrangement. The Manß(1 → 4)GlcNAc disaccharide may be used as a key intermediate for elaboration into more complex N-glycan structures providing a route to N-glycan oxazolines as donor substrates for ENGase enzymes that is considerably shorter than those reported previously.


Assuntos
Galactanos/metabolismo , Mananas/metabolismo , Oxazóis/metabolismo , Gomas Vegetais/metabolismo , Poligalacturonase/metabolismo , Polissacarídeos/metabolismo , Configuração de Carboidratos , Galactanos/química , Mananas/química , Oxazóis/química , Gomas Vegetais/química , Polissacarídeos/química
15.
Chemosphere ; 226: 782-790, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30965249

RESUMO

Etoxazole is a newly registered and widely used acaricide. However, its metabolites were not fully understood and might exhibit similar or even higher toxicity than parent compound. Therefore, in this study, the metabolites of etoxazole in citrus, soil and earthworms were firstly identified by an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). Four potential metabolites in citrus, 11 in soil, and 8 in earthworms were determined. These metabolites were then further structural elucidated based on the fragment pathways, and accurate mass measurement. The distributions of etoxazole and its main metabolites (M1, M2, M3, M4 and M5) which were identified as the dehydrogenation, hydrolysis, oxidation products of etoxazole (M0) were also monitored in citrus, soil and earthworms at different exposure periods. The 45 days exposure experiment showed that M0 gradually decreased in citrus and soil samples by 80% and 28% of the initial amounts, respectively. In earthworm samples, M0 accumulated in the bodies of the worms during 24 days exposure and then decreased with time. The dissipation rate of etoxazole were citrus > earthworms > soil. Concentrations of M1 and M3 in soil were found continuously increased with time during the experimental period. Moreover, the persistence of M1 in earthworm samples was also observed. Great attention should be paid to these two compounds due to their potential risks to both environmental and human health.


Assuntos
Citrus/metabolismo , Exposição Ambiental , Oligoquetos/metabolismo , Oxazóis/metabolismo , Solo/química , Acaricidas , Animais , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Espectrometria de Massas/métodos , Fatores de Tempo
16.
Nutrients ; 11(3)2019 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-30884817

RESUMO

Mg2+ deficiency may be involved in lifestyle-related diseases, including hypertension, cardiovascular diseases, and diabetes mellitus. Dietary Mg2+ is absorbed in the intestine mediated through transcellular and paracellular pathways. However, there is little research into what factors upregulate Mg2+ absorption. We searched for food constituents that can increase the expression levels of Mg2+ transport carriers using mouse colonic epithelial MCE301 cells. Cyanidin, an anthocyanidin found in black beans and berries, increased the mRNA levels of Mg2+ transport carriers including transient receptor potential melastatin 6 (TRPM6) channel and cyclin M4 (CNNM4). The cyanidin-induced elevation of Mg2+ transport carriers was blocked by GW6471, a peroxisome proliferator-activated receptor α (PPARα) inhibitor, but not by PPARγ, PPARδ, and protein kinase A inhibitors. Cyanidin-3-glucoside showed similar results to cyanidin. Cyanidin increased the protein levels of TRPM6 and CNNM4, which were distributed in the apical and lateral membranes, respectively. The nuclear localization of PPARα and reporter activities of Mg2+ transport carriers were increased by cyanidin, which were inhibited by GW6471. The cyanidin-induced elevation of reporter activity was suppressed by a mutation in a PPAR-response element. Fluorescence measurements using KMG-20, an Mg2+ indicator, showed that Mg2+ influx and efflux from the cells were enhanced by cyanidin, and which were inhibited by GW6471. Furthermore, cyanidin increased paracellular Mg2+ flux without affecting transepithelial electrical resistance. We suggest that cyanidin increases intestinal Mg2+ absorption mediated by the elevation of TRPM6 and CNNM4 expression, and may constitute a phytochemical that can improve Mg2+ deficiency.


Assuntos
Antocianinas/farmacologia , Proteínas de Transporte de Cátions/efeitos dos fármacos , Magnésio/metabolismo , PPAR alfa/efeitos dos fármacos , Compostos Fitoquímicos/farmacologia , Animais , Linhagem Celular , Colo/citologia , Células Epiteliais/metabolismo , Glucosídeos/farmacologia , Mucosa Intestinal/citologia , Deficiência de Magnésio/metabolismo , Camundongos , Oxazóis/metabolismo , RNA Mensageiro/metabolismo , Canais de Cátion TRPM/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo , Regulação para Cima
17.
Pharmacol Biochem Behav ; 180: 22-31, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30825491

RESUMO

Clinical evidence indicates that positive allosteric modulators (PAMs) of GABAA receptors have analgesic benefit in addition to efficacy in anxiety disorders. However, the utility of GABAA receptor PAMs as analgesics is compromised by the central nervous system side effects of non-selective potentiators. A selective potentiator of GABAA receptors associated with α2/3 subunits, KRM-II-81(5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazo[1,5-a][1,4]diazepin-3-yl)oxazole), has demonstrated anxiolytic, anticonvulsant, and antinociceptive effects in rodents with reduced motoric side effects. The present study evaluated the potential of KRM-II-81 as a novel analgesic. Oral administration of KRM-II-81 attenuated formalin-induced flinching; in contrast, diazepam was not active. KRM-II-81 attenuated nociceptive-associated behaviors engendered by chronic spinal nerve ligation (L5/L6). Diazepam decreased locomotion of rats at the dose tested in the formalin assay (10 mg/kg) whereas KRM-II-81 produced small decreases that were not dose-dependent (10-100 mg/kg). Plasma and brain levels of KRM-II-81 were used to demonstrate selectivity for α2/3- over α1-associated GABAA receptors and to define the degree of engagement of these receptors. Plasma and brain concentrations of KRM-II-81 were positively-associated with analgesic efficacy. GABA currents from isolated rat dorsal-root ganglion cultures were potentiated by KRM-II-81 with an ED50 of 32 nM. Measures of respiratory depression were reduced by alprazolam whereas KRM-II-81 was either inactive or produced effects with lower potency and efficacy. These findings add to the growing body of data supporting the idea that α2/3-selective GABAA receptor PAMs will have efficacy and tolerability as pain medications including those for neuropathic pain. Given their predicted anxiolytic effects, α2/3-selective GABAA receptor PAMs offer an additional inroad into the management of pain.


Assuntos
Analgésicos/farmacologia , Sinergismo Farmacológico , Formaldeído/farmacologia , Oxazóis/farmacologia , Medição da Dor , Receptores de GABA-A/metabolismo , Nervos Espinhais/cirurgia , Adjuvantes Anestésicos/farmacologia , Administração Oral , Alprazolam/administração & dosagem , Alprazolam/farmacologia , Analgésicos/administração & dosagem , Analgésicos/metabolismo , Analgésicos/uso terapêutico , Animais , Comportamento Animal/efeitos dos fármacos , Diazepam/farmacologia , Relação Dose-Resposta a Droga , Moduladores GABAérgicos/administração & dosagem , Moduladores GABAérgicos/farmacologia , Ligadura , Masculino , Neuralgia/tratamento farmacológico , Oxazóis/administração & dosagem , Oxazóis/metabolismo , Oxazóis/uso terapêutico , Ratos , Ratos Sprague-Dawley
18.
J Virol ; 93(12)2019 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-30918071

RESUMO

HIV-1 replication requires direct interaction between HIV-1 reverse transcriptase (RT) and cellular eukaryotic translation elongation factor 1A (eEF1A). Our previous work showed that disrupting this interaction inhibited HIV-1 uncoating, reverse transcription, and replication, indicating its potential as an anti-HIV-1 target. In this study, we developed a sensitive, live-cell split-luciferase complementation assay (NanoBiT) to quantitatively measure inhibition of HIV-1 RT interaction with eEF1A. We used this to screen a small molecule library and discovered small-molecule oxazole-benzenesulfonamides (C7, C8, and C9), which dose dependently and specifically inhibited the HIV-1 RT interaction with eEF1A. These compounds directly bound to HIV-1 RT in a dose-dependent manner, as assessed by a biolayer interferometry (BLI) assay, but did not bind to eEF1A. These oxazole-benzenesulfonamides did not inhibit enzymatic activity of recombinant HIV-1 RT in a homopolymer assay but did inhibit reverse transcription and infection of both wild-type (WT) and nonnucleoside reverse transcriptase inhibitor (NNRTI)-resistant HIV-1 in a dose-dependent manner in HEK293T cells. Infection of HeLa cells was significantly inhibited by the oxazole-benzenesulfonamides, and the antiviral activity was most potent against replication stages before 8 h postinfection. In human primary activated CD4+ T cells, C7 inhibited HIV-1 infectivity and replication up to 6 days postinfection. The data suggest a novel mechanism of HIV-1 inhibition and further elucidate how the RT-eEF1A interaction is important for HIV-1 replication. These compounds provide potential to develop a new class of anti-HIV-1 drugs to treat WT and NNRTI-resistant strains in people infected with HIV.IMPORTANCE Antiretroviral drugs protect many HIV-positive people, but their success can be compromised by drug-resistant strains. To combat these strains, the development of new classes of HIV-1 inhibitors is essential and a priority in the field. In this study, we identified small molecules that bind directly to HIV-1 reverse transcriptase (RT) and inhibit its interaction with cellular eEF1A, an interaction which we have previously identified as crucial for HIV-1 replication. These compounds inhibit intracellular HIV-1 reverse transcription and replication of WT HIV-1, as well as HIV-1 mutants that are resistant to current RT inhibitors. A novel mechanism of action involving inhibition of the HIV-1 RT-eEF1A interaction is an important finding and a potential new way to combat drug-resistant HIV-1 strains in infected people.


Assuntos
Transcriptase Reversa do HIV/efeitos dos fármacos , Fator 1 de Elongação de Peptídeos/metabolismo , Fármacos Anti-HIV/farmacologia , Células HEK293 , Infecções por HIV/tratamento farmacológico , Transcriptase Reversa do HIV/metabolismo , HIV-1/fisiologia , Células HeLa , Humanos , Oxazóis/metabolismo , Oxazóis/farmacologia , Inibidores da Transcriptase Reversa/farmacologia , Transcrição Reversa/efeitos dos fármacos , Sulfonamidas/metabolismo , Sulfonamidas/farmacologia , Replicação Viral/efeitos dos fármacos
19.
ACS Chem Biol ; 14(4): 674-687, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-30785725

RESUMO

Environmental and pathogenic microbes produce siderophores as small iron-binding molecules to scavenge iron from natural environments. It is common for microbes to produce multiple siderophores to gain a competitive edge in mixed microbial environments. Strains of human pathogenic Acinetobacter baumannii produce up to three siderophores: acinetobactin, baumannoferrin, and fimsbactin. Production of acinetobactin and baumannoferrin is highly conserved among clinical isolates while fimsbactin production appears to be less common. Fimsbactin is structurally related to acinetobactin through the presence of catecholate and phenolate oxazoline metal-binding motifs, and both are derived from nonribosomal peptide assembly lines with similar catalytic domain orientations and identities. Here we report on the chemical, biochemical, and microbiological investigation of fimsbactin and acinetobactin alone and in combination. We show that fimsbactin forms a 1:1 complex with iron(III) that is thermodynamically more stable than the 2:1 acinetobactin ferric complex. Alone, both acinetobactin and fimsbactin stimulate A. baumannii growth, but in combination the two siderophores appear to compete and collectively inhibit bacterial growth. We show that fimsbactin directly competes with acinetobactin for binding the periplasmic siderophore-binding protein BauB suggesting a possible biochemical mechanism for the phenomenon where the buildup of apo-siderophores in the periplasm leads to iron starvation. We propose an updated model for siderophore utilization and competition in A. baumannii that frames the molecular, biochemical, and cellular interplay of multiple iron acquisition systems in a multidrug resistant Gram-negative human pathogen.


Assuntos
Acinetobacter baumannii/metabolismo , Proteínas de Bactérias/metabolismo , Complexos de Coordenação/metabolismo , Imidazóis/metabolismo , Ferro/metabolismo , Oxazóis/metabolismo , Periplasma/metabolismo , Sideróforos/metabolismo , Acinetobacter baumannii/efeitos dos fármacos , Proteínas de Bactérias/química , Complexos de Coordenação/química , Humanos , Imidazóis/química , Imidazóis/farmacologia , Ferro/química , Estrutura Molecular , Oxazóis/química , Oxazóis/farmacologia , Ligação Proteica , Sideróforos/farmacologia
20.
Methods Mol Biol ; 1946: 259-270, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30798562

RESUMO

Siderophores are high-affinity iron chelators produced and used by bacteria to prosper under iron-limiting conditions they normally encounter in the environment and hosts. In this chapter, we describe the isolation and purification of the siderophores acinetobactin and baumannoferrin produced by the bacterial pathogen Acinetobacter baumannii using XAD-7 batch adsorption and high-pressure liquid chromatography (HPLC). We also describe chemical tests and biological assays used to detect the presence of catechol and hydroxamate siderophores in culture supernatants, XAD-7 extracts, and HPLC fractions.


Assuntos
Acinetobacter baumannii/metabolismo , Imidazóis/química , Imidazóis/isolamento & purificação , Oxazóis/química , Oxazóis/isolamento & purificação , Sideróforos/química , Sideróforos/isolamento & purificação , Catecóis/química , Catecóis/isolamento & purificação , Técnicas de Química Analítica , Cromatografia , Cromatografia Líquida de Alta Pressão , Imidazóis/metabolismo , Oxazóis/metabolismo , Sideróforos/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...